SIENTIAPDE-1110

Enhance MLFlow activity to sort data by created_at and remove duplicates; update tests to reflect changes

laborious/activities/mlflow.py

@@ -44,6 +44,11 @@ class MLFlow(BaseActivity):
         self.logger.debug("Raw input data:")
         self.logger.debug(data)
 
+        # Sort by created_at in descending order and keep first occurrence of each variable/timestamp pair
+        data = data.sort_values('created_at', ascending=False).drop_duplicates(
+            subset=['variable', 'timestamp'], keep='first'
+        )
+
         data = data.pivot(
             index='timestamp', columns='variable',
             values='value')